Voltage Null Points of a Mechanical Meter Bridge

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SUMMARY

The discussion centers on the concept of voltage null points in a Mechanical Meter Bridge, specifically addressing the conditions under which point D can be considered a null point compared to point B. The user argues that if the resistance of segment AD is less than that of segment AB, then point D should exhibit a higher potential than point B, resulting in current flow from D to B. However, the textbook states that when the jockey is connected to the left of D, no current flows through wire B, indicating a misunderstanding of the null point conditions. This discrepancy highlights the importance of accurately assessing resistance and potential differences in electrical circuits.

PREREQUISITES
  • Understanding of electrical resistance and potential difference
  • Familiarity with the principles of a Mechanical Meter Bridge
  • Knowledge of Ohm's Law and its application in circuit analysis
  • Basic concepts of current flow in electrical circuits
NEXT STEPS
  • Study the principles of Mechanical Meter Bridges in detail
  • Review Ohm's Law and its implications for circuit behavior
  • Explore the concept of null points in electrical measurement
  • Investigate common misconceptions in electrical circuit analysis
USEFUL FOR

Students and educators in physics or electrical engineering, particularly those studying circuit analysis and measurement techniques using Mechanical Meter Bridges.

Shreya
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Homework Statement
The answers of this question is mentioned to be A & C. My question is why isn't B true?
Please be kind to help
Relevant Equations
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My reasoning is that the wire has a resistance/unit length. The resistance of AD must equal that of AB for D to be called a null point. If we move jockey to the left, the resistance of AD decreases, thereby decreasing the potential drop across it. This means that the V of D is more than that of B causing a current to flow from D to B. So according to me B should be an answer, while the textbook says.
 

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when jockey is connect to the left of D no current in the wire B. that is why its wrong
 
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salmanshu322 said:
when jockey is connect to the left of D no current in the wire B. that is why its wrong
I cannot understand why it is so. Could you please explain? According to my reasoning the resistance of AD< that of AB. Therefore, the V drop across AD is lower making D at a higher potential than B, causing a current to flow from D to B.
 

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